Assessing the Success Rate and Costs of Common Recruitment Strategies for a Community-Based Environmental Health...

Recruitment is a vital component of public health research to produce generalizable findings and analytical power for subgroup differences in health outcomes. Recruitment strategies in population-based health studies vary widely with limited information on response rates and expected costs.

To evaluate recruitment strategies to better inform future recruitment planning and practices based on response rates, implementation costs, and demographics of enrolled participants.

We cross-sectionally examined recruitment data from the Colorado Study on Community Outcomes from Per- and polyfluoroalkyl Substances (PFAS) Exposure (CO SCOPE). Passive strategies included announcements and word-of-mouth referrals; active strategies included in-person outreach via door-to-door canvassing and/or tabling at community events, and phone or email contact to participants from a previous study. We calculated response rates per population reached by each strategy and estimated costs of materials and staff time.

In 2021-2023, we recruited and enrolled participants from 4 communities in El Paso County, Colorado. This site was part of a national multisite study of exposure to per- and polyfluoroalkyl substances in drinking water and associated health effects. We enrolled 916 adult participants (92% of our goal).

Overall participant response rate across all strategies was 0.5%. Response rates were lowest after announcements (0.1%), and highest from direct contact with previous study participants (32.3%). In-person outreach accrued the greatest number of enrolled participants but also at the highest estimated cost ($242/enrolled participant). Word-of-mouth referrals recruited the greatest proportions of young adults (aged 18-34) and people with a high school education or less. Ultimately, the enrolled study population over-represented older adults, women, and non-Hispanic White people compared with the target communities.

Recruitment strategies differed substantially in response rates and cost effectiveness. Word-of-mouth referrals and in-person outreach were most successful in recruiting diverse populations.